I am new to linux and xlib and would appreciate some advice regarding how to avoid BadWindow Errors during a XQueryTree function call.

Here's the issue...
1) My code is attempting to handle FocusIn, DestroyNotify and other events.
2) When an existing Window is deleted(closed), it appears that I receive a FocusIn event first instead of the expected DestroyNotify event.
3) My FocusIn event logic uses XQueryTree to determine who the parent is for the window that just came into focus. This works fine for normal FocusIn event scenarios. However, it appears that while I am looping through trying to determine who the eldest parent window is, the DestroyEvent starts to occur and causes my XQueryTree to error out. I was expecting the DestroyEvent to come in first, but maybe it does have to come into Focus before it is actually deleted when clicking on the right upper corner "X" button.
4) I even specified a Error Handler routine in an attempt to recover from the error, but XQueryTree still errors out.
5) If the window is being deleted, I don't even want to call XQueryTree in the first place.

What would be the best way to handle this? I am running on Fedora 14.

Thanks,
Larry

Well, as it turns out... I was able to use XSetErrorHandler to recover from the described error condition. Too bad XQueryTree isn't a little more resilient, especially since windows can come and go at anytime.